Radiation pattern improvement in closely-packed array antenna by using mushroom-like EBG structure

Three E-plane coupled closely-packed microstrip patch antenna array have been investigated. The three structures are: normal microstrip antennas (MA), MA with a group of mushroom-like electromagnetic bandgap(EBG) structure (traditional design), MA with three group of mushroom-like units(new design). Each group is consisted of two columns and twelve lines of the mushroom-like units. The simulated results show that by using the new design, the mutual coupling reduced from -15.74 dB to -26.33 dB with the reduction of 10.59 dB and lateral and backward radiation pattern decreased 13.19dB and 7.76dB respectively.